Screw anchor installing method and apparatus



4 Sheets-Sheet l O. R. ROWE ET AL Dec. 5, 1967 SCREW ANCHOR INSTALLING METHOD AND APPARATUS Filed Nov. 16, 1965 o, R. ROWE ET AL 3,356,163 SCREW ANCHOR INSTALLING METHOD AND APPARATUS Filed Nov. 16, 1965 Dec. 5, 1967l 4 Sheets-Sheet 2 ww @Sila Dec. 5, 1967 Q R, ROWE ET AL 3,356,163

SCREW ANCHOR NsTALLING METHOD AND APPARATUS 4 Sheets-Sheet 5 Filed Nov. 16, 1965 w Tf www m RM @m uw o. R. Rows ET AL 3,356,163

SCREW ANCHOR INSTALLING METHOD AND APPARATUS Dec. 5, 1967 United States Patent Office 3,356,163 v Y SCREW ANCHOR INSTALLING METHOD AND APPARATUS Oliver R. Rowe and William J. Dixon, Charlotte, N.C., assignors to R. H. Bouligny Inc., Charlotte, N.C., a corporation of North Carolina Filed Nov. 16, 1965, Ser. No. 508,124 Claims. (Cl. 173-43) ABSTRACT OF THE DISCLOSURE A method and apparatus arranged to install screw anchors in a manner causing the screw anchor to reach its installed position in the earth by axial advancement in accordance with the helical pitch of the anchor screw flange as the anchor is rotated to effect its installation, so that minimal earth disturbance occurs during installation and secure installation results are much facilitated.

- The present invention relates to a method and apparat-us for installing screw anchors, and more particularly to a method and apparatus that is capable of installing screw anchors effectively to take full advantage of the holding capacity of the ground while indicating the soundness of the installation as the screw anchor is being installed and disposing the screw anchor simply and accurately in proper holding alignment.

The installation of screw anchors has heretofore involved considerable disruption of the soil strata by the rotating screw flanges during installation to the extent that the holding capacities of the installations have been signilicantly impaired. This soil disruption, combined with general soil variations and the unpredictable nature of the holding capacity of the ground, has heretofore required independent testing of the screw anchors following installation, adding considerably to the overall time and expense of installation. In addition, the installation of screw anchors has heretofore required considerable time and experience in positioning the anchors preparatory to and d-uring installation in alignment with the direction of the guy wire or other attachment, Whic-h direction may vary considerably from one installation to the next.

Each of these ditculties is substantially minimized with the method and apparatus of the present invention by which the advance of the screw anchor is controlled during installation so that the screw flange advances along its helix without unduly disturbing the soil, the force necessary to cause rotation is sensed during installation as a concurrent indication of the holding capacity of the soil to determine when a necessary holding capacity has been attained, and the screw anchor is simply and readily positioned in proper alignment without complicated and repeated adjustment.

` Briefly described, the present invention involves the method of and the apparatus for ground installation of screw anchors of the type incorporating a screw flange by applying an axial force to the screw anchor suiiicient to maintain helical advance of the flange along the helix thereof upon rotation -of the screw anchor, while applying torque to the screw anchor sucient to cause rotation thereof upon application of the axial force, and while allowing the rotated screw anchor to advance into the ground :axially in accordance with the pitch of the screw ange thereof, thereby minimizing the soil digging action of the screw flan-ge. In addition, the present invention provides for sensing the magnitude of the applied torque for determining when the screw flange has advanced into ground of suicient soundness for holding the screw anchor adequately so that the installing operation may be 3,356,163 Patented Dec. 5, 1967 elciently stopped as soon as adequate soundness is obtained and without independent, subsequent testing being necessary. Further, the present invention provides for supporting the screw anchor on a boom that is manipulatable about an end closely adjacent the ground at the point of installation so that the screw anchor can be positioned simply and readily in proper position for and during installation.

The 'features and advantages of the present invention are incorporated in the preferred embodiment that is described in detail hereinbelow and illustrated in the accompanying drawings, in which:

FIG. l is a side elevation of a self-propelled vehicle carrying the preferred embodiment of the apparatus fo' installing screw anchors according to the present invention with the apparatus disposed in an inoperative position for traveling;

FIG. 2 is a View similar to FIG. l showing the apparatus in an operating position with a screw anchor partially installed;

FIG. 3 is =a side elevation as viewed from the side opposite that illustrated in FIG. 2;

FIG. 4 is an end elevation as viewed from the left in FIG. 2 with the screw anchor supporting boom in fully elevated position and showing the extreme sidewise positions of the boom in light dot-dash lines;

FIG. 5 is an enlarged side elevation, partially in section, of the carriage and :adjacent boom portion of the apparatus -as seen in FIG. l;

FIG. 6 is a vertical sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is a vertical sectional view taken along line 7-7 of FIG. 5; and

FIG. 8 is a diagrammatic illustration of the hydraulic system of the illustrated apparatus.

In the embodiment illustrated, the screw anchor installing apparatus is mounted on a self-propelled vehicle that is seen to be a crawler-type tractor 10 on which the apparatus may conveniently be transported over rough terrain to different locations. The tractor 10 has mounted thereon means 12 for supporting a screw anchor A in proper position for installation, means 14 for applying an -axial force to the screw anchor A, means 16 for applying a torque to the screw anchor A to cause rotation thereof, means 18 for sensing the magnitude of the applied torque, and means 20 for applying a reverse axial force to an installed anchor for testing the holding capacity of the installation.

The supporting means 12 includes a framework 22 extending along the opposite sides of the tractor 10 and on which are lxed horizontal pivot pins 24 for pivotally mounting the ends 26 of the arms 28 of a supporting yoke 30 that forms a movable support component and extends across the rear end of the tractor 10 for pivoting about the horizontal axis of the pivot pins 24. The yoke 30 is manipulated by a hydraulic piston-cylinder unit 32 pivoted at one end on the framework 22 with the other end pinned to one corner of a triangular rocker plate 34 that extends downwardly to a pivot mounting 36 on the framework 22 and extends forwardly to form a pivot support 3S for the end of a connecting rod 40 that has its other end pivotally secured in an upstanding bracket 42 on one of the arms 28 of the yoke 30. The pistoncylinder unit 32, rocker plate 34 and connecting rod 40 operate in a Vertical plane as means acting on the movable support component or yoke 30 to effect pivoting thereof about its horizontal pivot axis.

The yoke 30 supports a pair of spaced brackets 44 extending outwardly from its base 46 for pivoted mounting of a horizontal trunuion bar 48 therebetween, which trunnion bar has end pins 50 seated in the brackets 44 for v pivoting of the bar 48 about its horizontal axis. Extending 3 upwardly from and fixed to the trunnion ba-r 48 is a trunnion shaft 52 that extends through a pivot plate 54 seated on the trunnion bar 48 for' pivoting thereagainst about the trunnion shaft 52 as an axis. The shaft 52 extends outwardly to an attachment toy a cross-plate 56, which, along with the pivot plate 54, are components of a screw anchor supporting boom 58 that isy universally pivoted at its' lower end 60 on the yoke 30 through this attachment of the' plates 54- and 56 on the trunnion shaft 52 and trunnion bar 48.

The screw anchor supporting boom S8 is formed with elongated latticework bottom and side walls 62 and 64, respectively, with the aforementioned pivot platel 54 secured to' the lower en-d of the bottom wall 62 and the aforementioned cross-plate 64 secured to and extending between the ends of the side walls 64 at a spacing from the bottom wall 62.4 The boom 58 is universally pivoted by manipulating means having first and second components opera-ting in generally perpendicular planes. One of these components is an elevating cylinder-piston unit 66 having one end universally pivoted in a double pin mounting 68 on the adjacent arm- 28 of the yoke 30 at a spacing from the pivot of the boom 58 and its other end secured in a similar mounting 70 near the outer end of a side Wall 64 of the boom 58. The elevating unit 66 is disposed generally in a vertical plane and is operated hydraulically to pivot the boom 58' vertically about the trunnion bar 48. The other manipulating means component is a side angle adjusting cylinder-piston unit 72 having one end attached to a single pivot mounting 74 on an: extension 76 ofthe trunnion bar 48 and its other end attached to a single pivot mounting 78 on the adjacent side wall 64 at a substantial spacing from the trunnion shaft '2. As a result of this attachment the side angle adjusting cylinder-piston unit- `72 pivots with the boom 58 about the axis of the trunnion bar 48 and is hydraulically operated to pivot the boom about the trunnion shaft 52, with the double pivot attachments of the elevating cylinder-piston unit 66 accommodating such pivoting.

Extending the length of the boom 58 is a linear guideway formed by a pair of elongated channel bars 80` that constitute the outer edges of the side walls 64. These bars 80 have oppositely facing channels 82 for the slidable supportv and guidance ofl a carriage 84 on the underside of which are a set of fourleading rollers 86 and a pair" of trailing rollers 88 (FIGS. 5, 6 and 7). One of the trailing rollers 88' and two of the leading rollers 86 are seated in each channel bar 80 and eachV of the rollers is tapered to the contour of the channel 84. The trailing rollers 88 are mounted for rotation ori the ends of a transverse trailing shaft 90 that is supported in a pair of spaced blocks 92 depending from the underside of the carriage 8`4 with washers 94' spacing the trailing rollers 88' from the blocks 92.

The four leading rollers 86 are arranged in pairs with each pair mounted for rotation on a longitudinal side plate 96,- with each of the two side plates 96 connected intermediate the supported rollers to a transverse rocker' shaft 98- supported in a pair of spaced blocks 100 depending from the underside of the carriage 8'4.

Small exterior rolls 101 depend from the carriage 4l about vertical axes outwardly of and engaging the sides of the channel bars 80 to retain the carriage 84 generally centered with respect to the channelbars so as to prevent binding ofthe leading or trailing rollers 86 and' 88 in the channels 82.

Linear movement of the carriage 84 along the guideway is accomplished by the aforementioned axial force applying means 14, which includes' an endless chain 162 disposed centrally of the boom 58 and extending longitudinally thereof. It is trained around a drive sprocket 104 mounted in' a vertical planel at the lower end of the boom 58 on a drive shaft 106 that extends between an' opstanding post 106 on the boom 5'8' and a hydraulic drive motor unit 110 on the boom, whichv motor unit rotates the shaft 106 to drive the chain 102. The other end of the chain 102 is trained around an idler sprocket 112 mounted for rotation on a horizontal idler shaft 114 carried in a pair of take-up frames 116 at the upper ends of the boom side walls 64, which take-up frames 116 are adjustable to control the slack in the chain 102. The upper reach of the chain 102 extends along theA guideway below the level of the carriage trailing and rocker shafts 90 and 98, respectively, and is drivingly connected to the trailing shaft 90 to move the carriage 84 along the boom 58 by a connecting link 118 that is pinned to the chain 102 and carried on the trailing shaft 90.

Mounted onthe carri-age 84 isthe aforementioned torque applying means 16, which includes a hydraulic torque motor unit 120 that operates through a gear unit 122, to rotate a screw anchor connection 1,24 about an axis parallel to the guidew'ay andto which connection 12'4- tlie upper end of a screw anchor' A is connected for ground installation along a line parallel to the boom 58 with the hydraulic drive motor unit acting' through the' chain 102 and carriage 84 to1 apply a'n axial force' to thescrew anchor and the torque motor unit 120 acting through the gear unit 122 to apply a torque to the screw anchor A sufficient to cause rotation' thereof when the axial force is being applied. Both the axial for-ce applying means 14 and the torque` applying means 16l are retained in following relation with the' screw' anchor A as it advances during installation due to' the fact. that both means are associated with the carriage 84, which advances along the boom' 58 during installation.

The two motors 110 and 120, as welll asthe yoke' op"- eratirig cylinder-piston unit 32,. boom elevating cylinderpiston unit- 66, and' side` angle adusting cylinder-piston unit 72, are driven by a main hydraulic tanden'r pumpI 126 mounted at the front of the tractor 1.0 and driven. by the motor thereof` through` a drive shaft extensionl 1.28.` The pump 126 circulates the hydraulic fluid' to" th'e aforementioned operating units from a reservoir in the hydraulic tank 130 mounted on the framework 22 at the' side of thev tractor 10.

Also operated by the main hydraulic pump 1:26 is af pair of spaced stabilizing and testing, cylinder-piston units 132 that extend longitudinally at the lower endof the Iboom 58. These' cylinder-piston? units 132 arev slidably mounted in spaced tubular sleeves 134 secured to= outwardly extending struts 136 at the lower end' of the side walls 64,- which struts position the sleeves in. parallel straddling relation with respect tok the screw anchor A.` Mounted at the lower ends of the testing cylinder-piston: units 1.32 through double pivot connections 138 is a pair of stabilizing feet 140 having elongated bottom faces 142 to which are secured. cleats 144 that seat the bottom faces 142 firmly against the ground without significant slippage.

The upper ends of the stabilizing and testing. cylinderpiston units 132 are alternatively connectedV in fixed relation to the sleeves 134 for use of the units as pressure means to stabilize the boom 58 on the feet 1'40 during installation of screw anchors, or in fixed relation. to an installed' screw anchor t'o operate as pressure means for applying a reversel axial force or loadj thereto for testing purposes. To provide for such alternate attachment, the upper ends of the cylinder-piston tl'nits' 132 are formed with attaching heads 146 having apertu'red flanges 148 for pinned attachment of removable' links 150 that extend from the head flanges 148' to similar removable pinned attachment in apertnre'd flanges 152 01T the sleeves 134, the attaching heads 146 also having transverse slots 154 for seating of the ends of a testing yoke 156 to which is adjustably bolted atie' bar 158 that extends longitudinally downward along the boom 58 irlv axial alignment with an installed screw anchor A in the hook of the outer end of which it is removably' attached 75 for applying a reverse testing loa-d tothe installed anchor by the cylinder-piston units 132 acting between the stabilizing feet 140 and the yoke 156-.

The hydraulic system that operates all of the abovedescribed components is illustrated diagrammatically in FIG. 8, in which the drive shaft extension 128 is shown drivingly connected to `both the high-power component 126 and low-power component 126 of the hydraulic tandem pump 126. The high-power pump component 126' is connected, through a three-Way valve 160 to the aforementioned torque motor unit 120 that applies torque to the screw anchor A to cause rotation thereof. Connected between the high-power pump component 126' and the three-way torque control valve 160 is the aforementioned means 18 for sensing the torque applied to the screw anchor. In the embodiment illustrated, this torque sensing means 18 is a simple pressure gauge that indicates the hydraulic pressure lbeing applied to the torquemotor unit 120, which pressure is directly proportional to the applied torque.

The three-way torque control valve 160 is manipulated by manual operation of a control lever 162 that operates to position the valve in a central closed position (FIG. 8) at which the torque motor 120V is disconnected 4from the pump 126 and is, therefore, inoperative, or in either of the extreme positions, which oppositely connect the pump 126 with the motor for motor rotation yin opposite directions. In either of the extreme positions the valve directs fluid circulation to the motor and back to the valve from which the fluid ows to the return line 164 leading to the reservoir tank 130.

The high-power hydraulic pump component 126' also is operable, through another three-way valve 166, to drive the aforementioned chain drive motor 110 in either direction to move the carriage 84 along the linear guideway of the boom 58` to position the carriage preparatory to or following anchor installation. The threeway valve 166 is controlled by manipulation of the lever 168 and the hydraulic fluid circulates from the valve 166 to the drive motor 110, back to the valve 166 and thence through the return line 164 to the reservoir tank 130.

VA -by-pass valve 170 is connected as a take-oif between the high-power pump component 126 and the valve 166 and leads to the return line 164 to the reservoir tank 130 to accommodate fluid flow during operation when the three-way valves 160 and 166 are both closed.

The chain drive motor 110 is connected to the lowpower pump component 126 through a three-way valve 172 that is connected in parallel with the aforementioned valve 166 lfor alternative driving of the chain drive `motor 110 by either pump component 126' or 126". Settable pressure relief valves 174 connect a return line 176 with each side of the chain drive motor 110 between the motor and the three-way valve 172 on the low-power vside to; limit the maximum pressure to the chain drive .motor 110 in either direction of 4hydraulic ilow as reversibly controlled by the three way valve 172. In effect,

- these pressure relief valves 174 result in the maintenance of a substantially constant pressure at the chain -drive pump 110, which produces a substantially conlstant axial force applied to thek screw anchor A thereby,

and, as the relief valves 174 are arranged in parallel relation with respect to the three-way valve 166 from the high-power pump4 component 126', they similarly con- ;trol the pressure and resulting axial force applied by the high-pressure pump component 126. The three-way .valve172 on the low-power side is controlled by manual operation of the lever 178.

Connected through the central position of the threeway valve 172 to the low-power pump component 126 is a three-way high-pressure test valve 180, to which is .similarly connected a three-way low-pressure test valve 182. The yhigh-pressure test valve 180 controls the sta- .bilizing and testing cylinder-piston units 132 directly so that the full force of the low-power motor can be exerted as a reverse axial load to an installed screw anchor attached to the yoke 156, whereas the low-pressure test valve 182 is connected to the stabilizing and testing cylinder-piston units 132 through a settable relief valve 184 that limits the testing force to a desired maximum. Thus the high-pressure test valve and the low-pressure test valve 182 function alternatively to apply different test loads, the amounts of which loads are indicated by the pressure gauge 186 that is responsive to the testing pressure from either valve when either valve is in testing position. The high-pressure test valve 180 is reversible for retraction of the cylinder-piston unit 132, but check valves 188 render the reverse position of the low-pressure test valve 182 nonfunctional. The test valves 180 and 182 are controlled by manually operated levers 196 and 198, respectively.

Another settable relief valve 190 is disposed in a return line 192 that leads from the connection between the low-power pump component 126 and the adjacent three-way valve 172 to the aforementioned return line 176. This relief valve determines the maximum pressure in the low-power side of the system, and particularly in the high-pressure test segment. Also located between the low-power pump component 126" and the adjacent threeway valve 172 is a pressure gauge 194 that indicates the actual pressure in the low-power side.

Connected in series to the low-pressure test valve 182 and in series with each other are three three-way valves 200, 202, and 204, which are operated by levers 208, 210, and 212, respectively, to control manipulation of the boom 58. The first of these three valves is a boom elevation control valve 200 that is connected to the aforementioned elevating cylinder-piston unit 66 to control operation thereof by the low-power pump component 126" .to raise and lower the boom 58.

The second of the three series valves is a side angle adjusting control valve 202 that is connected through orifices 206 to the aforementioned side angle adjusting cylinder-piston unit 72 to control operation thereof by the low-power pump component 126 to pivot the boom 58 sidewise. The orifices 206 serve to reduce the pressure ito the cylinder-piston unit 72 to increase the acting time of the cylinder-piston unit for reliable control of the boom adjustment.

The third of the three series valves is a yoke manipulating control valve 204 that is connected to the laforementioned yokel manipulating cylinder-piston unit 32 to control operation thereof by the low-power pump component 126 to pivot the yoke 30 about its horizontal axis to raise or lower the disposition of the boom 58 that is supported on the yoke 30.

The optimum hydraulic pressure desired at these three series valves 200, 202, and 204 for operation of their respective cylinder-piston units 66, 72 and 32 is not necessarily the same as the pressure desired for operation of the preceding components of the low-power side of the hydraulic system as determined by the aforementioned settable relief valve 190. Normally the pressure desired at the three series valves is less than that desired for the preceding components as a low pressure provides more reliable control of the operation of the cylinder-piston units. To provide this lower pressure at these three valves and to provide a low by-pass pressure when all of the valves on the low-power side are in closed position, a settable relief valve 214 is connected as a take-off between the low-pressure test valve 182 and the boom elevation control valve 200.

Leading from this -relief valve 214 to the return line -176 to the reservoir tank i130 is a secondary return line 216, which is also connected to the return side of each of the three series valves 200, 202, and 204.

All of the above-described three-way valves and their operating levers are mounted on a control panel 218 at the rear of the tractor 10 with the levers disposed at the top of the panel for convenient access by the operator while seated on the tractor. As these levers and valves and their mounting on the control panel 218 are conventional,

they are not shown in the accompanying drawings other than in the diagrammatic illustration of the hydraulic system in FIG. 8'.

`The above-described apparatus is operated easily and readily to install screw anchors, such as the screw anchor A illustrated in FIGS. 2 and 3, which is a conventional type having a single helix screw iiange F. The apparatus is operable as well to install other types of screw anchors, as, for example,l multiple helix types and can be installed by direct connection of the apparatus to the outer end' of the anchor as shown or by utilizing a conventional tubular wrench attached to the anchor above the helical flange and extending to the outer end` of the anchor for attachment to the installingapparatus.

In using the apparatus to install a screwv anchor for anchoring of a guy wire or other line t'o support a structure such asa high-power electrical transmission line tower, the tractor driver first drives the tractor to the location with the boom 58 lowered andthe yoke 30 raised in travelling position as seen in FIG. I. The driver then manipulates the tractor 1.0 to align the boom 58 in rough alignment with the point on the ground at which the anchor is to be installed and the point at which the guy wire is to be attached to the supported structure.

The lever 212 of the yoke manipulating control valve 204 is then manipulated to operate the piston-cylinder unit 32 to lower the yoke into close proximity to the ground and the tractor is moved to position the lower end 60 of the boom 58 closely adjacent the point on the ground at which the screw anchor is to he installed and at which a screw anchor A is disposed' awaiting attachment to the apparatus. This positioning of the end of the boom adjacent the ground in combination with the above-described universal pivoting ofthe hoorn about its lower end permits simple manipulation of the boom in any direction while maintaining it substantially centered on the point of anchor installation such that complex readjustment is not required.

The lever 208 of the boom elevation control valve 200 is then manipulated to operate the elevating cylinderpiston unit 66 to elevate the boom 58` tothe proper inclination as determined by pre-calculation', which inclination is indicated by the clinome'ter 220 on the side wall 64 of the boom.

The lever 210 of the side angle adjusting control valve 202 is then manipulated t'o operate the side angle adjusting cylinder-piston unit 72 to make whatever sidewise adjustment of the boom may be necessary for final alignment. This sidewise adjustment is normally slight, but can be over a range indicated by the light line showing in FIG. 4 when necessary, as when the terrain or other conditions require initial positioningof the tractor out of boom alignment.

The lever 19'6 of the high-pressure test valve 180 is then manipulated, with the links 150 fixing the stabilizing and testing cylinder-piston units 132' to the boom sleeves 134, to extend the cylinder-piston units to seat the stabilizing feet 140 against the ground for stabilization of the boom S8 during subsequent operation. As the cylinder-piston units 132 are connected in parallel they will inherently adjust to any unevenness in the terrain.

The carriage 84 is then run down the boom to the end of the anchor by manipulating the lever |168 of the chain drive motor valve 1'66 onr the high-power side of the system, which drives the chain drive motor 110 to advance the carriage 84. The upper end of the anchor is then attached in a conventional manner by the screw anchor connection 124 to the apparatus.

Actual installation is then begun by manipulating the lever 162 of the valve 160 that operates the torque motor unit 120 from the high-power pump component |126' to rotate the screw anchor A, and at the same time manipulating the lever 178 of the valve 172 that operates the chain drive motor110 from the low-power pump component 126 to apply an axial force to the screw anchor A through the chain 102 and carriage 84.

The axial force applied is preferably of a magnitude sufficient to maintain advance of the screw anchorA along the helix of the screw ange F when the anchor is rotated, and the torque applied must beV suiieient to overcome the resistance' of the ground to rotation. This resistance varies with the ground conditions and alsoy is indicative of the holding power of the anchor installation as the resistance is substantially greater and is directly proportional` to the soundness of the ground whi:h holds the anchor, thus the torque that must be applied to-overcome the ground resistance is directly proportional to the soundness of the installation and the pressure gaugey 18 can be read in terms of soundness of the ground at the depth of the anchor at the time of reading. Because of this relationship, the installing operation can be. stopped as soon as sufficient holding strength is obtained and testing of every installed anchor becomes unnecessary.

Occasionally it may be advisable to make a sample test of the strength of an installed screw anchor. This can be done simply by the present apparatus without' even moving the tractor or any of its components except to disconnect the links 150 for the stabilizing and testing cylinder-piston units 1132 and attaching the test yoke 156 in the slots 154 ot' the cylinder-piston unit heads 146. The tie bar 158 is then bolted to the test yoke 156 and secured to the end of the installed screw anchor, following which either the lever 196 of the high-pressure test valve 180 or the lever 198 of the low-pressure test valve 182 is manipulated to operate the cylinder-piston units 132 toapply a reverse axial load to the anchor against the stabilizing feet |140, with the load being predetermined land imposed by setting the relief valves 190l (for high-pressure testing) on 184 (for low-pressure testing).

In the embodiment illustrated, the high-power pump component 126 is of a 3-horsepower capacity andthe low-pressure pump component 126- is of a 3/a-horsepower capacity. The chain drive motor unit is of a 21A-horsepower capacity and exerts an axialforce of about 2,500 pounds, while the torque motor unit is of a 3- horsepower capacity and applies a torque of up to 5,200 foot-pounds. In testing, the high-pressure test through the high-pressure test valve applies a load of up to 27,000 pounds and the low-pressure test through the low-pressure test valve 182 and relief valve 184 applies a load of up to 18,000 pounds. These values can of course be varied to suit particular requirements or conditions.

The present invention has been described in detailhereinabove for purposes of illustration only and is not intended to be limited by this description or otherwise exccpt as defined by the appended claims.

We claim:

1. An apparatus for installing screw anchors in the ground comprising means for supporting a screw anchor in position for installation, means for applying an axial force to said supported screw anchor sufhcient to maintain helical advance of the screw anchor ange along the helix thereof upon rotation of the screw anchor during ground installation, and means for applying torque to the screw anchor sufficient to cause rotation thereof upon application of said axial force during ground installation,

all of said means acting to allowr the rotated screw anchor to advance axially in accordance with the pitch of the screw frange thereof.

2. The apparatus defined in claim 1 and further characterized by means for sensing the magnitude of torque applied by said torque applying means to determine when said screw flange has advanced into ground' of-'suicicnt soundness for holding said screw anchor adequately.

3. The apparatus defined in claim 2 and further characterized in that said axial force applying means is operated hydraulically to apply an axial force of substantially constant magnitude, said torque applying means-is operalcd hydraulically, and said sensing means senses the magnitude of the hydraulic applying means.

4. An apparatus for installing screw anchors in the ground comprising a supporting framework, a boom mounted on said framework, means carried by said boom for supporting a screw anchor during ground installation for axial advancement along said boom, means for applying torque to said screw anchor sutlcient to cause rotation thereof during ground installation, and means for applying an axial force to said screw anchor sucient to maintain axial advance thereof along said boom in accordance with the screw flange pitch of said anchor upon rotation thereof during ground installation.

5. An apparatus for installing screw anchors in the ground comprising a supporting framework, a boom mounted on said framework and having a linear guideway thereon, a carriage mounted on said boom for linear movement along said guideway, means mounted on said carriage for engaging a screw anchor and applying torque thereto sulicient to cause rotation thereof during ground installation, and means acting on said carriage to apply an axial force to said screw anchor suiiicient to maintain axial advance of the screw anchor along said boom in accordance with the helical pitch of the screw llange thereof upon rotation of the screw anchor during ground installation and causing said carriage to follow said screw anchor to maintain said application of axial force as said screw anchor advances axially.

6. An apparatus for installing screw anchors in the ground comprising a supporting framework, a boom mounted on said framework for universal pivotal movement about an end thereof closely adjacent the ground, means carried by said boom for supporting a screw anchor during ground installation for axial advancement along said boom, means for manipulating said boom about said end to position said Screw anchor in desired disposition for ground installation, said manipulating means having first and second components acting on said boom in planes generally perpendicular to each other to produce universal pivoting of said boom, means for applying torque to said screw anchor to cause rotation thereof during ground installation, and means for applying an axial force to the screw anchor'to cause axial advancement along said boom in accordance with the helical pitch of the anchor screw flange upon rotation thereof during ground installation.

7. The apparatus defined in claim 6 and further characterized in that said supporting framework includes a movable support component on which said boom end is pivotally mounted, and by means acting on said movable support to position said pivoted boom end closely adjacent the ground.

8. An apparatus for installing screw anchors in the ground comprising a self-propelled vehicle, a supporting yoke pivotally mounted on said vehicle for pivoting about a horizontal axis, a boom mounted on said yoke with one end universally pivoted thereon, means for pivoting said yoke to position said one end of the boom closely adpressure applied by said torque jacent the ground, means carried by said boom for supporting a screw anchor during ground installation for axial advancement along said boom, means for universally pivoting said boom to position a supported screw anchor in desired disposition for ground installation, means for applying torque to said screw anchor to cause rotation thereof during ground installation, and means for applying an axial force to the screw anchor to cause axial advancement along said boom in accordance with the helical pitch of the anchor screw lflange upon rotation thereof during ground installation.

9. An apparatus for installing screw anchors in the ground comprising a supporting framework, a boom mounted on said framework, means carried by said boom for supporting a screw anchor during ground installation for axial advancement along said boom, means for applying torque to a supported screw anchor to cause rotation thereof during ground installation, means for applying an axial force to said screw anchor to cause axial advancement in accordance with the helical pitch of the anchor screw flange upon rotation thereof during ground installation, and means supported on said boom for applying a reverse axial force on said screw anchor after installation for testing the holding strength of the installation.

10. An apparatus for installing screw anchors in the ground comprising a supporting framework, a boom mounted on said framework, means carried by said boom for supporting a screw anchor during ground installation for axial advancement along said boom, means for applying torque to a supported screw anchor to cause rotation thereof during ground installation, means for applying an axial force to said screw anchor to cause axial advancement in accordance with the helical pitch of the anchor screw flange upon rotation thereof during ground installation, a pair of spaced stabilizing feet straddling said screw anchor, and pressure means connected between said feet and said boom for pressing said feet against the ground to stabilize said boom during Screw anchor installation, said pressure means being alternatively connected between said stabilizing feet and the outer end of an installed screw anchor to apply a reverse axial load to said screw anchor to test the holding strength of the installation.

References Cited UNITED STATES PATENTS 2,255,241 9/1941 Brown 173-43 X 2,393,392 4/1946 Page l73-20 X 2,856,155 10/1958 Putt 173-28 X 2,972,388 2/1961 Thornburg 173-147 X 3,148,739 9/1964 Mattingly et al 173-46 3,220,494 11/1965 Cannon et al 173--28 X MARTIN P. SCHWADRON, Primary Examiner. FRED C. MATTERN, Examiner. L. P. KESSLER, Assistant Examiner. 

1. AN APPARATUS FOR INSTALLING SCREW ANCHORS IN THE GROUND COMPRISING MEANS FOR SUPPORTING A SCREW ANCHOR IN POSITION FOR INSTALLATION, MEANS FOR APPLYING AN AXIAL FORCE TO SAID SUPPORTED SCREW ANCHOR SUFFICIENT TO MAINTAIN HELICAL ADVANCE OF THE SCREW ANCHOR FLANGE ALONG THE HELIX THEREOF UPON ROTATION OF THE SCREW ANCHOR DURING GROUND INSTALLATION, AND MEANS FOR APPLYING TORQUE TO THE SCREW ANCHOR SUFFICIENT TO CAUSE ROATATION THEREOF UPON APPLICATION OF SAID AXIAL FORCE DURING GROUND INSTALLATION ALL OF SAID MEANS ACTING TO ALLOW THE ROTATED SCREW ANCHORTO ADVANCE AXIALLY IN ACCORDANCE WITH THE PITCH OF THE SCREW FLANGE THEREOF. 